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make it a little rougher and you might see some interesting things. however, what i was getting at, is that paintballs may already be rough enough that you wont see any difference between them and a dimpled ball.

they do go fairly far...

"The Fine Print: Discontinue use if your eyeballs suddenly get way smaller."

star, apg had a system that actually had a spinning barrel to test ball spin on flight i believe, so he could use that. or maybe they just thought of using one. anyways, id like to hear from tom what he found instead of us guessing

This is all being discussed in Deep Blue. Long story short typical paintball spin has little to do with paintball accuracy. The dimples made the accuracy worse. We tried all types of induced spins with no appreciable increase in accuracy.

Just for fun, i think AGD should go to a driving range with either a flatline model 98 or one of those z mags, reason being golfballs or rather the drivers were designed specifically to impart backspin on the golf ball thereby making the range of the golf ball, or air time longer.

I noticed that people don't seem to get the concept of fluid dynamics, or have come close but to no conclusion.

For the record, dimples are used a lot. I wouldn't call baseball, football, etc. cutting edge technology. Rather, I would look at F1 racing, naturally aspirated low displacement motors (motorbikes and Honda B series motors).

There are several terms to be looked at here. There is flow velocity, flow capacity and flow quality. Flow velocity would be how fast a fluid travels. Flow capacity would be how much of that fluid travels. Flow quality would be the nature in which that fluid travels.

When air comes out of air conditioners, flows across airplane wings, or is sucked into a motor it travels in layers. This is called laminar flow. The air travels in layers that are "laminated" upon eachother. In the actual paintgun, I doubt air travels in a laminar form, since the air spends time compressed and decompressing. That would be turbulent flow. However, it is the flight of the ball that we look at when the ball is in flight. We want the ball to fly as straight and far as possible (a perfect straight line could never be achieved b/c of gravity).

So, what would cause a ball to fly through air with as little resistance as possible? When two surfaces rub against eachother, they are going to have some kind of friction coefficient. Without going into the math part of it, I can tell you that some surfaces have worse coefficients of friction than others, or they aren't as "slick". In machines, smooth surfaces are good for less friction and easier movement. This is not the case in fluid flow. The smoother a surface is, the worse a fluid will travel over it. B/c the surface is smoother, there is more surface area present to create more laminar drag. When I say laminar drag, I mean that fluid does not flow as well, causing a "pile up". This slows down the flow velocity.

Take the head off your motor and polish everything to a crystal smooth surface. You will destroy it's performance namely because you have destroyed it's airflow or it's ability to breathe. Why do sharks have rough skin?

So how do the dimples help out? The dimples help out because they reduce the surface area that the air flows over. This allows for better flow velocity and less laminar drag.

Don't think a paintball's speed is so minute and small that dimples and the such won't make a difference. The mean flow velocity for most motors is about 240-260 fps. That's a little below what we run the muzzle velocities of paintballs at.

foam balls

On the topic of foam paintballs, I actually have a few. A friend of my dad's who owns a paintball store gave them to me, so don't ask where you can get them.

Of course, being the scientist that I am, I decided to test the nerf paintballs. In testing them (for the good of science, of course) I shot my mom with one and heard the most blood-curdling scream. The scream could of just come from shock from the noise of the paintball gun plus not expecting to get hit, but after about a year from that event I'm still not willing to ask her(remind her)about it.

I only have about a 100 of them left but I'll try to post a picture soon -Deadpool

I haven't been here in a while, but fluid mechanics and paintball are two of my favorites. Looking at the Reynolds number for a paintball traveling at 300 fps, it is high enough for a rough surface to be more beneficial to the drag coefficient than a smooth one, for a round sphere.( at least according to my text) I am not saying dimples, but perhaps a rough surface might reduce drag a bit. I am too busy at the moment to drop my other studies ( with finals coming up and all) to figure out the math if it will make a difference in range, but maybe in a few weeks. Has anyone done calculations/ experiments with rough paintballs?

I say that dimples are a good idea.In reference to baseball I will explain my theory. On the otherhand they may not be you decide

In baseball the ball is rough and matians a coat of air around it. During flight slowly the coat of air is brushed off causing a change in speed. First the baseball travels
much faster because air on air not air on leather. If you throw a biliard ball (pool table ball) it will travel slower. Because it is smooth surface and the coat of air is released much faster. Thus the baseball is more effectient in a rough surface not smooth. In relation to paint balls I beleve that it will have the same effect small pockets of air will get traped in the dimples. On the otherhand the purpution of the paint ball me differ the change. Because we need ,hpa nitrogen or co2 depending one what you use. That will be on the back side of the paint ball possibley causeing a diffrence of balance because air may or may not be heavyer or lighter. Thus mabey causeing a effect of flight. Well thats all the information I have at the moment. I will look into the subject.

Someone once asked me if I felt war was the answer.... For a moment I wondered then I replied "No War is not the answer, War is the question and the answer is Yes."

spin on dimples

I'd love to find foam paintballs. Do they seriously make them? I've seen plastic ones recently, sold on alot of paintball websites, but I don't want to use those on each other. Foam would be great, but I can't find them anywhere.

"Quit your crying, wipe off the splat, and get the hell off my field!" - Referee

Re: foam balls

Originally posted by DeadpoolNSH On the topic of foam paintballs, I actually have a few. A friend of my dad's who owns a paintball store gave them to me, so don't ask where you can get them.

Of course, being the scientist that I am, I decided to test the nerf paintballs. In testing them (for the good of science, of course) I shot my mom with one and heard the most blood-curdling scream. The scream could of just come from shock from the noise of the paintball gun plus not expecting to get hit, but after about a year from that event I'm still not willing to ask her(remind her)about it.

I only have about a 100 of them left but I'll try to post a picture soon -Deadpool

Consider this - a sharks skin is rough, and has little v-shapes in it - which has been proven to be more aerodynamic than a smooth surface - the only problem I see with this and paintball, you never know which way a paintball is going to fall into the chamber... making shaping kinda rough to do

"Unless someone like you cares a whole awful lot, nothing is going to get better. Its not" - Dr Suess

From what I hear, there is not enough spin on a paintball to make a difference. What if you tested a few of these paintballs with a flatline barrel or something of that nature that would give it an enormous backspin? Combining a flatline with a dimpled paintball could give you even more range.

Yeah, I don't think spin on a paintball will do much. I know it works for bullets in real guns but those bullets are an entirely different shape.

One problem I see with a dimpled paintball is that it would be near impossiblet to make the dimples consistant enough to have decent shot consistancy. But in theory, if the dimples were perfect, the ball would have considerably less drag.

have any of you every heard of the polaris golfball, or somethin like that. it was banned from golf cus it was to good. it only had like a 1/4 inch strip of dimples around the circumference of the ball. this made it go perfecly straight, even when purposly sliced. i saw it on the history channel or somethin. it sounds like the perfect p-ball if it would work

Originally posted by Jack & Coke I wonder how much that thing would curve if I shot it from my Tippy Flatline...

Damn thing would probably fly around and hit me in the forehead...

A few years ago, Dave Zupan showed me the holes in the ceiling tiles (tall ceiling in the workshop - it's like a warehouse building) made by these balls when they shot them through a gun set up to make backspin.

Up at the Finale, there were a few guys discussing a dimpled ball. According to what they told me, one of the major paintball manufacturers (I honestly don't remember which one..although I think it was JT), had managed to develope a process to produce a dimpled ball, or so they suspected. They claim to have come up with the idea at almost the same time, but apparantly didn't win the patent (or were waiting for results on it). Interesting stories, but I doubt we'll see anything new in the near future.

Take the head off your motor and polish everything to a crystal smooth surface. You will destroy it's performance namely because you have destroyed it's airflow or it's ability to breathe. Why do sharks have rough skin?

SuperBeast,

So why did Ford go to the trouble of ExtrudeHoning the SVT Contour intake plenums?

The purpose of Extrude Honing is not primarily to polish the ports of the cylinder head. The purpose is the same as conventional porting, get more airflow. It's done essentially by pumping an abrasive slurry through the ports, or at least that's how i understand it.

The reason Aircraft wings are shaped that way is to create lift. Not for a decrease in drag, although incedently that is what happens.

And just humor me on this one.

Now perhaps a teflon based shell with score linea across it. ( think longitude lines on a globe) and a latex based paint, think enough to allow the paintball to spin however will still be bright and shiny on your soon to be X friend.